Optimized Liquid Droplet Spray Device For An Inhaler Suitable For Respiratory Therapies

What is this patent about?

'934 is related to the field of liquid droplet spray devices, particularly those used in inhalers for respiratory therapies. The background involves challenges in efficiently atomizing liquids, especially suspensions, into droplets of a controlled size. Prior art devices struggle with issues like inconsistent droplet size, clogging of outlet orifices, incomplete emptying of the liquid reservoir, and the formation of liquid layers on the nozzle surface, all of which affect the accuracy and reliability of drug delivery.

The underlying idea behind '934 is to optimize the flow and throughput of the atomized liquid while minimizing retention within the device. This is achieved by creating a standing wave pattern within the liquid substance using a vibrating element and strategically positioning the outlet nozzles at the vibration mode peaks of this pattern. This arrangement ensures efficient ejection of the liquid, leading to a more precise and predictable dosage.

The claims of '934 focus on a liquid droplet spray device comprising a housing with a liquid-containing space, a vibrating element to generate liquid droplet spray, and outlet means for ejecting the spray. Crucially, the vibrating element creates a standing wave pattern, and the outlet nozzles are positioned to coincide with the vibration mode peaks of this standing wave pattern.

In practice, the device consists of two substrates forming a housing with a chamber for the liquid. A piezoelectric element, attached to the bottom substrate, vibrates the liquid at a specific frequency, creating the standing wave. The top substrate contains cavities connected to outlet nozzles via channels. By aligning the nozzles with the peaks of the standing wave, the liquid is efficiently atomized and ejected. The substrates can be coated with hydrophilic or hydrophobic materials to further optimize flow and minimize retention.

The key differentiation from prior approaches lies in the deliberate use of the standing wave pattern to enhance droplet ejection. Unlike earlier devices that relied on simple vibration or pressure to force liquid through nozzles, '934 leverages the resonant behavior of the liquid to achieve a more controlled and efficient atomization process. This results in a more uniform droplet size, reduced liquid retention, and improved dosage accuracy, making it particularly suitable for inhalers used in respiratory therapies.